Brake mechanism.



No. 890,933. PATENTED JUNE 16, 1908.

H. ROWNTREB. BRAKE Mmmmm APPLIOATIOIZ FILED MAR. 35, 1907.

' struction and economical to manufacture, and wherein, when pressure is applied, slack HAROLD ROWNTREE, OF CHICAGO, ILLINOIS.

BRAKE MECHANISM.

Specification of Letters Patent.

Patented June 16, 1908.

Application filed March 30, 1907. Serial No. 365,553.

T 0 all whom it may concern:

Be it known that I, HAROLD Rownrnnn, a citizen of the United States, residing at (hicage, county of Cook, State of Illinois, have made a certain new and useful Invention in Brake Mechanism, of which thefollowing is a specification.

This invention relates to brake mechanism.

The object of the invention is to provide a brake mechanism which is simple in condue to the wear of the parts is first taken up and when such pressure attains a predetermined degree, the full braking effort is accomplished.

A further object is to HOViClG a brake mechanism whereby the relative movement of the brake and its actuating devices automatically varies, the variationtaking place when a predetermined pressure is applied to the brake shoe.

A further object is to provide a brake which embodies means for applying the pressure through an automatic shifting of leverages.

A further object is to provide a brake mechanism in which the braking effort is applied througl'i an automatically shifting fulcrum, such shifting occurring when a predetermined pressure is applied.

Other objects of the invention will appear more fully hereinafter. I

The invention consists substantially in the construction, combination, loca ion, and relative arrangement of parts, all as will be more fully hereinafter set forth, as shown in the accompanying drawings, and finally pointed out in the appended claims.

Referring to the accompanying drawings, and to the various views and reference signs appearing thereon, Figure 1 is'a view showing one form of air brake mechanism embodying the principles of my invention. Fig. 2 is asimilar view showing a modified construction and arrangement embraced within the spirit and scope of my invention. Referring particularly to Fig. 1, reference sign S, designates the brake cylinder to which a pressure medium is supplied through pipe R, from any suitable control. To the rod 2, of piston 1, working in said cylinder, is pivotally connected, as at 4, a rocking arm 3, at a point intermediate its ends. To one end of this arm-3, as at 10,ispivotal1y connected a rack bar 6, arranged to mesh with and rotativel'y actuate a pinion 7, mounted upon or connected with a cam-8, the cam surface of which is arranged to bear against one end of a lever 9. The other end of said lever 9, is connected at 11, through a rod 12, to the opposite end of arm 3, as at 13. To the same end of arm 3, is connected one end of a stout spring 5, the other endof said spring being connected to a fixed part or bracket 20, or otherwise, as may be desired. At a point adjacent the bearing of its ends against the cam surface 8, the lever 9, is con nected through a link 14 with the lever 15, through which the brake rod 16, is operated, said lever 15, being connected by red 17, to the lever 18, for operating the correspond-- ing and cooperating brake rod 19,0f the brake rigging, in the usual or any well known, suitable or convenient manner or arrangement. The operation of the construction so far described is very simple. When pressure is admitted to the cylinder S, and the piston 1, begins to move therein, the arm 3, will be rocked about the point 13, by reason of the tension of the spring 5, being imposed thereon, and in. a direction to shift or move the rack bar 6 towards the right from the position shown in the drawing. In other words the arm 3, becomes a lover of the second order, the point 13, being the fulcrum, the power being applicsd'at point 4, and the work accomplished at the point 10. By the movement thu parted to the rack bar 6, the pinion 7, and with it the cam 8, is rotated, the cam surface bearing against the end-0f lever 5), and hence rocking said lever in a direction to cause a brake applying movement of the arms 15 and 1S, and the rods16 come and thereafter the arm 3 rocks about the point 10, as a ivot, and hence, pulling on the longarm of ever 9, its point of bearing contact a ainst the cam surface 8, becoming the to cram, a strong braking effort pressure is a I is applied to the brakes. In other wordsthe relative movement ofthe brake and its actuating mechanism automatically varies, the variation takin place when a predetermined p ied to the brake shoe.

In the mo 1fied construction shown in Fig.

2, and which is embraced within'the spirlt and scope of my invention, I have shown a somewhat different arrangement for accomplishing .the same result as above pointed out. In this construction Iemploy two cylinders A, and B, having the pistons .O, and

D, respectively. The'lpiston O, in cylinder A, operates a rack bar which meshesjwith 'a pinion L, attached to the hub of a cam J,

v Emu the cam surface of which bears one end of a lever F, the other end ofsaid lever being connected by a link E, to the piston D in cylinder B. A strong spring 8, is connected at one .end to the arm or lever'F, and

. at the other'end to a fixed bracket or support. An arm or rod G, is; also connected to the leverF, and throughwhich the brake shoes are operated in the usual or any ordi- As the piston nary, convenient or suitable manner. A spring T is also arranged to oppose the movement of the piston C, in cylinder A. Thepressure medium is admitted to cylinder A, behind piston 0, through port M, from any suitable or convenient source and under the usual or an desired system of control.

the impelling force of the pressure it causes the rack bar K to rotate pmion L, and with it the cam J, and hence causing lever F, 'to be rocked about its point of pivotal connection to link E, as a fulcrum. The rod G, is connected to the lever F, at a point closely adjacent the cam contact-end H, thereof, and hence the actuation of said rod G when the cam is revolved, is through a comparatively short levera c. This is sufiicient however to cause any ooseness in the brake rigging or any wear in the" brake shoes to be taken up and the brakes to be applied lightly.

When piston C has moved outwardlyby the air pressure behind it, the pressure at the a same 'timeenters' a port N, and a chamber 0,

in whi'ch'opera tes a plunger valve P, against a spring W, and which valve; controls a port R, through which the ressure medium is admitted to cylinder B, ehind the piston D,

therein. This does nottake place, however,

until a pressure is imposed upon the brakes which is. predetermined by the spring W, which, if desired may be made adjustable. When this predetermined pressure occurs, however, the pressure is admitted tocylinder 1B, and the piston D begins its movement.

Thereupon the fulcrum of lever F, is shifted to the end H, thereof which bears upon the cam J. Thereafter the lever F, is rocked about such fulcrum by the movement of t e piston Diand, operating through the inmid leverage, effects'a powerful applica- ,.begins to move out under sui'nption 'ofair without And I regardthis as a most tion of the braking pressure to the brakes. To insure the full release of the brakes in this form of construction, I employ thecheck valve T, which allows the pressure in cylin der B, free access into cylinder A, and so to the exhaust, after the pressure has been sufficiently reduced to cause the plunger valve P, to close the port R. a

A brake mechanism embodying the principles of my'inven-tion as above set forth, is eqir'lially Well adapted for the operation by ot er means and other ways than air pressure, as it is obvious that the piston rod 2,

for instance, inIfig. 1, when moved'b what ever means accomplishes a quick ta 'ng up of the slack and then a powerful application of the brakes; My invention, therefore, is not to be limited in its broadest scope to the air brake mechanism.

From this descriptiomit will be readily seenthat in both forms ofconstruction shown and described the relative movement of the brake and its actuating mechanism auto- .mat-ically varies, the variation taking placewhen a predetermined res'sure is ap lied to the brake shoe." It wil also be seen .t at the variation is accomplished by a shifting of leverage, such shifting being accomplished automatically, and when a predetermined pressure is applied to the brakes. Itwill also be seen that intheoperation of the brake important and valuable feature of my invehtion.

tion is automatically self adjusting to compensate for wearon the brakeshoes or. for any slackness or looseness that might exist .in the brake rigging. It will also be seen' that when the operating cylinder is opened to exhaust, the sprin brakes serves to hold t e long leverage connection rigid and in such relation as to enable the cam to operate on the short leverage connections at the next application of the brakes; Y and that when the cam is placed in operation, such operation continuesuntilthe brake pressure created or applied by its operation equals the power'or tension of; the. spring, and whenthat point is reached the long leverage connection is automatically brought into. play-to. perform its of making the final application ofbrake'fpressure.

changes in .thegletails of construction and arrangement would readily suggest them- It will also be seen thata brake mechp anism embodying the principles of my inven-L,

which releases the It is obvious that many variation s and- But ture of my invention and various c nstructions embodying the principles thereof, and having described suci constructions, their purposes, functions and modes of operation, what I claim as new and. useful and of my own invention, and desire to secure by Letters Patent is 1. In a brake mechanism, the combination with brake devices and means for applying the same including a pivoted lever, of means for shifting the fulcrum of said lever when a predetermined pressure is applied.

2. In a brake mechanism, the combination with brake devices, and a pivoted lever for o erating the same, of automatic means for slitting the fulcrum of said lever when a predetermined brake pressure is applied.

3. In a brake mechanism, the combination with brake devices and means for operating the same including a lever and means for varying the leverage exerted by said lever without varying the point of application of the power thereto, said Variation occurring when a predetermined pressure is applied.

4. In a brake mechanism, the combination with brake applying devices and means for operating the same, including a lover, of means for operating said lever through a short arm, to attain a predetermined pressure, and means for shifting the operation to the long arm of the lever when such predetermined pressure is applied.

5. In a brake mechanism, the combinationwith brakeapplying devices, and means for operating the same, including a lever, of means for operating said lever through a short arm to attain a predetermined pressure, and means for automatically shifting the operation to the long arm of the lever'when such predetermined pressure is attained.

6. In a brake mechanism, the combination with brake applying devices, and means for operating the same, said means including a shifting fulcrum, of means for shifting such fulcrum when a predetermined braking pressure is applied. i

7. In a brake mechanism, the combination with brake applying devices, and means for operating the same, including a lever, a cam arranged to operate on the short arm of the lever, means for operating the cam, and means fortransferring the operation to the long arm of the lever when the braking pressure attains a predetermined degree.

8. In a brake mechanism, brake applying devices, a lever for operating the same, a cam arranged to operate against the short arm of said lever and means for automatically trans- IIaving now set forth. the object and na-- l I l l ferring the application of power to the long mm of the lever when a prmletern'iined pressure is applied through the cam.

H. In an airbrnke nwchanism, brake applying devices, alerer for operating the same,

in. power cylinder and piston, means connected to said piston for operating said lever through a short arm, and means, whereby \[lltl'l a predetermined pressure is applied to the action .ol the piston is automatically transferred to the long arm of the lover.

It). .ln an air brake mechanism, brake applying dcvices, a lever for operating the same, a power cylinder and piston means connected to said piston for operating said lever 'through a short arm, and means, whereby when a pre letcrmined pressure is applied through the short arm of said lever said piston operates upon the long armof said lever.

l 1,. In a brake lllfl'liitlllSlll, brake applying devices, a lover, a cam against which said lever bears at one end, a rod connected to the other end of said lever and brake applying devices, connections between said lever and brake applying devices, said connections being adjacent the end of said lever which. bears against said cam, means for operating said cam, to apply pressure to the brakes, and means, whereby when said pressure attains a'predetermincd degree said rod is operated to increase the leverage.

12. In an air brake mechanism, brake applying dcvices, a lover, a cam against whichv said lever bears at one end, a rod connected to the other end of said lever, connections between said lever and the brake applying devices, said cmrnections being adjacent that end of the lever which bears against the earn, a cylinder and piston, and connections be tween said piston and cam and rod for operating the same.

13. In an air brake mechanism, brake applying devices, a lever, connections between said lever and brake applying devices, an arm respectively connected at the ends thereof to the ends of said lever, a cylinder and piston, said piston connected to said arm, and a spring connected to said arm.

14. In an air brake mechanism, brake applying devices, an arm, a piston and cylinder, said piston connected to said arm, and connections between the respective ends of said arm and the brake applying devices.

15. In an air brake mechanism, brake applying devices, an arm, a piston and cylinder, said arm pivotally connected intermediate its ends to the stemof said piston, a spring connected to said arm, and connections between the respective ends of said arm and the brake applying devices.

.16. In an air brake mechanism, brake applying devices, a piston and cylinder, an arm pivotally connectedintermediate its ends and to the stem of said piston, a lover, a rod connecting one end of said lever and one end of said arm, cam engaging the other end of a said lever, means actuated by the other end of said arm for moving said cam, connections between said lever and the brake applying devices, and a spring arranged to act upon said, arm. v i

a In testimony whereof I have hereunto set HAROLD ROWNTREE. Witnesses:

J OSEPII 'KLEIN, S. E. DARBY. 

